The present invention involves packing articles, as nested stacks of containers, generally plastic containers, preferably in a vertical orientation with the open end down. The stacks are packed into packing cartons. Typically, this is a time consuming operation which is performed manually after articles such as cups, margarine or yogurt tubs or similar containers have been stacked by any one of a number of known methods.
An automated apparatus for packaging stacked cups is described in German Patent No. 37 41 257, published Jun. 15, 1989. This patent discloses a gripping apparatus for picking up, transporting and horizontally placing a stack of nested cup shaped articles into a packaging container. A long curved retainer rotates about the central axis of the stack of cups to trap the stack against a flat fixed stop. This device places a stack in a horizontal orientation in the packaging carton. This means that removal of individual cups from the carton would be awkward at best. Generally, an entire stack must be removed in order to remove an individual cup. In addition, horizontally packed stacks tend to separate during handling and shipping.
U.S. Pat. No. 5,136,826 shows an apparatus for preparing an array of stacked articles for insertion into a packaging carton. In operation, the open end of the carton is manually placed over the array. Then, the articles and carton are manually or semi-automatically inverted and the carton is sealed. This represents a time consuming and inconvenient operation involving a great deal of hand labor.
U.S. Pat. No. 5,212,390 describes an apparatus for loading tall, upright containers into packing cases. This apparatus consists of two conveyors, one above the other, and a flight bar conveyor with an inclined path between the other two conveyors. The upright containers are moved in parallel in-line columns along the upper feed conveyor until they are gripped by depending pegs. The pegs carry and guide the containers down into the packing cases along the inclined path. Although this apparatus can pack tall containers vertically into a packing case, it could not be used to vertically pack stacks of cups or tubs or the like since only a portion of the height of the articles to be packed could be grasped. The remainder of the stack would separate.
U.S. Pat. No. 5,212,932 discloses an apparatus for vertically loading articles into a packaging carton so that the articles are upright in the carton. In accordance with the disclosed apparatus, an array of articles to be packaged is positioned above a carrier. The carrier has finger assemblies for receiving, holding and transporting the articles to the carton. The fingers can be opened to release the articles into the container. The apparatus requires a considerable amount of space between and around adjacent articles or stacks to allow the fingers to release the articles. This means that the articles or stacks cannot be packaged very densely resulting in wasted space and/or loose articles in the package.
European Patent Application 0 124 951, published Nov. 14, 1984, discloses a stacked article packaging apparatus wherein the stacks are allowed to drop on their sides into an open box so that they are lying down in the box. A predetermined number of articles are stacked vertically onto a rotatable carrier with a tilting table which then drops the stack onto a conveyor. This apparatus is not capable of packaging the stacks vertically and allows them to drop twice; once from the carrier and again from the conveyor into the carton. Dropping the stack is a tenuous operation and could result in some of the article separating from the stack and causing a jam.
Accordingly, it is a principal object of the present invention to provide an apparatus for packing articles, as elongated, non-rigid articles, or flexible articles, or nested stacks of containers.
It is a particular object of the present invention to provide an apparatus as aforesaid for packing nested stacks of containers in a vertical orientation, with if desired the open end down, which is efficient and convenient to do and which is not prone to separation of the nested stacks.
Further objects and advantages of the present invention will appear hereinbelow.